tracing/stat: do some cleanups
- remove duplicate code in stat_seq_init()
- update comments to reflect the change from stat list to stat rbtree
[ Impact: clean up ]
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 8030ec9..17f20eb 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -93,10 +93,15 @@
typedef int (*cmp_stat_t)(void *, void *);
-static void
-insert_stat(struct rb_root *root, struct stat_node *data, cmp_stat_t cmp)
+static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp)
{
struct rb_node **new = &(root->rb_node), *parent = NULL;
+ struct stat_node *data;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+ data->stat = stat;
/*
* Figure out where to put new node
@@ -118,12 +123,13 @@
rb_link_node(&data->node, parent, new);
rb_insert_color(&data->node, root);
+ return 0;
}
/*
* For tracers that don't provide a stat_cmp callback.
- * This one will force an immediate insertion on tail of
- * the list.
+ * This one will force an insertion as right-most node
+ * in the rbtree.
*/
static int dummy_cmp(void *p1, void *p2)
{
@@ -131,15 +137,14 @@
}
/*
- * Initialize the stat list at each trace_stat file opening.
+ * Initialize the stat rbtree at each trace_stat file opening.
* All of these copies and sorting are required on all opening
* since the stats could have changed between two file sessions.
*/
static int stat_seq_init(struct stat_session *session)
{
struct tracer_stat *ts = session->ts;
- struct stat_node *new_entry;
- struct rb_root *root;
+ struct rb_root *root = &session->stat_root;
void *stat;
int ret = 0;
int i;
@@ -154,23 +159,12 @@
if (!stat)
goto exit;
- /*
- * The first entry. Actually this is the second, but the first
- * one (the stat_list head) is pointless.
- */
- new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);
- if (!new_entry) {
- ret = -ENOMEM;
+ ret = insert_stat(root, stat, ts->stat_cmp);
+ if (ret)
goto exit;
- }
- root = &session->stat_root;
- insert_stat(root, new_entry, dummy_cmp);
-
- new_entry->stat = stat;
/*
- * Iterate over the tracer stat entries and store them in a sorted
- * list.
+ * Iterate over the tracer stat entries and store them in an rbtree.
*/
for (i = 1; ; i++) {
stat = ts->stat_next(stat, i);
@@ -179,22 +173,16 @@
if (!stat)
break;
- new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);
- if (!new_entry) {
- ret = -ENOMEM;
- goto exit_free_list;
- }
-
- new_entry->stat = stat;
-
- insert_stat(root, new_entry, ts->stat_cmp);
+ ret = insert_stat(root, stat, ts->stat_cmp);
+ if (ret)
+ goto exit_free_rbtree;
}
exit:
mutex_unlock(&session->stat_mutex);
return ret;
-exit_free_list:
+exit_free_rbtree:
reset_stat_session(session);
mutex_unlock(&session->stat_mutex);
return ret;
@@ -207,7 +195,7 @@
struct rb_node *node;
int i;
- /* Prevent from tracer switch or stat_list modification */
+ /* Prevent from tracer switch or rbtree modification */
mutex_lock(&session->stat_mutex);
/* If we are in the beginning of the file, print the headers */
@@ -280,7 +268,7 @@
}
/*
- * Avoid consuming memory with our now useless list.
+ * Avoid consuming memory with our now useless rbtree.
*/
static int tracing_stat_release(struct inode *i, struct file *f)
{